Dark/Light Mode

[NikkSaan]

I have a script which I use to toggle between dark/light mode a few times a day using gsettings.
Any Ideas on how I can trigger a colorscheme change in lite-xl from my script?

I'd like to avoid using subprocess to listen on events from gsettings in lite-xl.
Is there any way I can catch a Unix signal in lite-xl? Or trigger a (user) module reload externally?

I looked at some of the code for lite-xl but I'm not a programmer and I'm guaranteed to miss something.
Any suggestions or code would be appreciated!

[Guldoman]

I'd like to avoid using subprocess to listen on events from gsettings in lite-xl.

Why? That would probably be the simplest way.

Is there any way I can catch a Unix signal in lite-xl? Or trigger a (user) module reload externally?

Not really. But you could use the dirmonitor functionality to check if a file has been modified, and act accordingly.

If the script is purely time-based, you could replicate it as a Lite XL plugin.

If this is about the same toggle that directs https://wiki.libsdl.org/SDL3/SDL_GetSystemTheme, when we port to SDL3 we'll add a listener for that.

[NikkSaan]

For anyone interested, here is my solution.
It's one of those "it works on my machine" ones!
And it will only switch the colorscheme after lite-xl is focused.

-- mod-version:3
local core = require "core"

local gsettings = process.start({
   "sh", "-c", 
   "gsettings get     org.gnome.desktop.interface color-scheme;" ..
   "gsettings monitor org.gnome.desktop.interface color-scheme"
})

core.add_thread(function() 
  
  while gsettings:running() do
    local color_scheme = gsettings:read_stdout()
    if string.find(color_scheme, "default") then
      core.reload_module("colors.summer")
    elseif string.find(color_scheme, "dark") then
      core.reload_module("colors.default")
    end
    coroutine.yield(1)
  end 

end)

[Guldoman]

Oh this looks great!

A little warning: process:read_stdout can return partial results if you time it wrong enough.
You could do something like:

-- mod-version:3
local core = require "core"

local gsettings = process.start({
  "sh", "-c",
  "gsettings get     org.gnome.desktop.interface color-scheme;" ..
  "gsettings monitor org.gnome.desktop.interface color-scheme"
})

if not gsettings then
  -- Not really correct, as we're directly running sh, not gsettings
  error("Could not start gsettings. Is it installed?")
end

local function parse_output(s)
  if string.find(s, "default") then
    core.reload_module("colors.summer")
  elseif string.find(s, "dark") then
    core.reload_module("colors.default")
  end
end

core.add_thread(function()
  local output = ""
  while true do
    local buf = gsettings:read_stdout()
    if not buf then break end
    if #buf > 0 then
      output = output .. buf
      repeat
        local line, remainder = string.match(output, "(.-)\n(.*)")
        if line then
          output = remainder
          parse_output(line)
        end
      until not line
    end
    coroutine.yield(.250)
  end
  core.warn("gsettings process died")
end)

which will deal with partial outputs and quick theme changes (for example by double clicking the theme button).

This could become a proper plugin! Feel free to PR it in the plugins repo.

[NikkSaan]

Thank you for your input!! Yes, this solves the problem of consecutive theme changes.
The bigger annoyance is that the theme will change only after the window is focused. It makes the whole thing feel half baked.
Now you see why I didn't want to use subprocess - too many caveats... :(

Better leave this feature for SDL3 to handle.

[Guldoman]

The bigger annoyance is that the theme will change only after the window is focused. It makes the whole thing feel half baked.
Now you see why I didn't want to use subprocess - too many caveats... :(

The issue is not on the process part but on how Lite XL handles core.add_thread.
Basically we stop every "thread" when we lose focus. It was done to avoid using CPU while inactive, but it has obvious drawbacks..
We will change that in a future release.